They discovered that by the age of 11, one in five children whose mums were educated to degree level or higher were overweight, compared to one in three of those whose mothers had fewer qualifications.

Once the researchers had taken into account factors such as the child’s sex and ethnicity, and the mother’s age when the child was born, they found that several other factors were still significantly associated with an increased risk of the child being overweight by the time they were 11 years old. These included high birthweight, being breastfed, and consumption of solid foods before four months of age.

Dr David Taylor-Robinson, the study’s lead author, said: “Our study has shown that socioeconomic circumstances at birth, as measured by mother’s educational attainment remained significant after adjusting for all other influential factors.

“We also found that the risk of a child being overweight by the age of 11 increased the more heavily the mother smoked during her pregnancy, even after taking into account other potentially influential factors.”

“Policies to support mothers to maintain a healthy weight, breastfeed and abstain from smoking during pregnancy are important to improve maternal and child health outcomes, and our study provides evidence that they may also help to address the continuing rise in inequalities in childhood overweight,” Dr Taylor-Robinson concluded.